Valve seat boring tool



Oct. 18, 1932. O ALBERTSQN 1,882,689

VALVE SEAT BORING TOOL Filed Feb. 18, 1929 3 Sheets-Sheet l Get. 18, 1932. o, ALBERTSON 1,882,689

YALVE SEAT BORING TOOL Filed Feb. 18, 1929 3 Sheets-Sheet 2 WIN] 110 0d. 18, 1982; F. o. ALBERTSQN 1,882,689

VALVE SEAT BORING TOOL 32 II I I I I I I I I I I 33 h I I Patented Oct. 18, p

UNITED. STATES PATENT OFFICE FRANK; O. ALBERTSON F SIOUX CITY,- IOWA ASSIGNOR TO ALBERTSOIT & COMPANY.

INC., 01 SIOUX CITY, IOWA, A CORPORATION OF IOWA V VALVE SEAT BORING 'TOOL Application filed February 18, 1929. Serial 110.840,?70.

The present invent on relates to valveseat and from. the accompanying drawings in reconstruction tools, and is particularly 0011- which similar characters of. reference indicerned with tools for refacingorreconstruct- Cate similar parts throughout the several ing valves of internal combustion engines. views. a e i The tools of the present invention may be Referringto thedrawingsof which there used both for ref-acing the valve seat by are three sheets: I p means of reamers or other surfacing tools, Fig. 1 is a view in perspective of the valve or they may be employed for cutting a recess seat reconstructiontool applied to the block adapted to receive a new metal ring form ng of an internal combustion engine; r

: a new valve seat. Fig. 2 is a plan view of the tool with the One of the objects of the invention is the ratchet lever removed; provision of an improved method of recon- Fig. 3 is a sectional view taken on theplane struction of valve seats. j of the line 33 of Fig. 2; 2

Another object is the provision of im- Fig. 4 tea sectional view through the tool l 'iproved valve seat reconstruction tools, and engine block taken in Fig. 1 on the plane whereby a valve seat may be refaced or -reof the l'ne corresponding to the line 4-4 of constructed with its axis in accurate align- F g.2; I ment with the axis .of a valve guide. Fig. 5 is a sectional view taken on the plane Another object is the provision of animof the line 5-5 of Fig. l;

lligroved method of valve-seat reconstruction, Fig. Gis a plan view of a springWaSher u in which the alignment and support of the used in the universal bearing; g cutting members is accomplished pr ncipally ,Fig. 7 is a sectional view taken on the plane by a pilot stem which is accurately and finedof the line 7 -7 of Fig. 6; ly secured in a valve seat guide. Fig. 8 is a sectional iew I Another object isthe provision of an imof the line S Sof Fig. 4; Y v

proved valve seat reconstruction tool which Fig. 9 is a sectional view taken on the plane is adapted to reinforce and support a pilot of the line 9-9 of Fig.8; v stem in an aligned position, while depending Fig. 10 is a view. similar to Fig. 4 showupon said pilot stem to perform the function ing the assembly of tools used in installing a of alignment. valve seat ring; a Another object of the invention is the pro.- Fig. 11 is a view in perspective of the drivvision of tools of the class described which ing tool; v

l are more simple, economicaland more sturdy .Fig. 12 is a view in perspective of a valve than the tools of the prior art. seat ring; Y

taken on the plane Another object is the provision of an as Fig. 13 is an elevational view of the antisembly of valve seat reconstruction tools, frictionbearing with the outer race removed, which is capable of performing heavy cutshowing'the ball bcaringring. ting operations without the tool binding in In the embodiment chosen to illustrate the its bearings, and which is capable of operainvention" (referring to. Figs. 1, 2 and 4),

Ttion with a mini m f ef ort. indicates the valve seat reconstruction tool Another object is the provision of a tool assembly in its entirety. The tool preferablyv of the class described having an improved includes a, cutter .21, a pilot stem 22, a'bear-'v gauge and feed mechanism capable of feeding 23, a tool, holder 2i,.and means for acing the cutter without changingits aligntuatingthe cutter which may consist of a -ment. ratchet lever 25, or other actuating devices. 7

Another object is the provision of a novel The ratchet lever may be of any conring installation tool and a novel method of ventional type, and as any type of actuating installation of valve seat rings. device may be used, the lratchet lever will I Other objects and advantages of the inven-, not be described in detail.

tion will be apparentfrom the description Many of the advantages of the invention m may be realized without employing all of the elements shown in the complete assembly, and it should be understood that the invention includes the use of the various sub-comf, binations and permutations of all of the elements described, wherever such combinations will be advantageous, and the scope of the invention is to be limited only by the terms of the appended claims.

he, Referring to Fig 1, thev conventionalinternal combustion engine block 26 is provided with a plurality of valve openings 27 hav ing valve seats 28 formed therein, and with a plurality of stud bolts 29.:forsecuringpthe motor head to the block. The valve seat tool assembly is illustrated in the operation of reconstructing a valve seat 28 by cutting a recess adapted to receive a metal member" forming a new valve seat.

20 The valve seat tool is preferably provided with a pilot stem 22 of the type] illustrated in the prior patent of. Frans O. Albertson,

No 1,806,189 dated May 19', 1931, which is' peculiarly adapted to accurately center'ita5 iselfaxially of any valve stem guide such as the guide 30, and adapted tobe fixedly mounted in the valve guide 30'by expanding the parts 31 of a tripartite end The pilot 'stem 22 is provided witha frustoao conical portion 32 spaced from the end 31 and adapted to engage the inner and upperf edge of the cylindrical valve guide 30, automatically centering the pilot stem at this point. Thelowerend of the pilot stem 22 35 is split three ways as at 33, forming three split portions 31 of equal thickness and adapted to be cammed apart by a earning member 34, which extends longitudinally of the pilot stem in the bore 35. The camniing member is pro ided with threads 36 adjacent iit s upper end adapted to be received complementary threads carried by the bore 35'and the ,cammingmember is provided a noncircular'head 37.

The functions or" such a pilot stem are fully set forth in the application above mentioned, sothat it will sufiice to say that since three points determine the location of acir cle, the tripartite end is peculiarlyadapted to'accurately center thelower end of the pilot stem 22 axiallyof thevalve guide 30 in a manner which cannot be accomplishedby any pilot stem notcon'structed according to the present invention. As the pilot stem is al- -ready centered at the point 38 of the valve guide ;30 by thecone 32, it will be observed thatthe pilot stem is accurately locatedwlth its axis coinciding with the axis of the valve guide 30, andthe'pilot stem is thus adapted to accurately support a cutter 21 or other iresurfacingtool, so that it may torm a valve seat having its axis accuratelylqcated in the axis of the valve guide. 7

The pilot stem 22 is also eculiarly adapted *to have the cammmg mem er -34place'd in a state of compression with the pilot stem 22 in a state of tension, so that the pilot stem becomes extremely stifi when located within a valve guide 30, as shown in Fig. 4.

It will thus be observed that the pilot stem of the present invention is peculiarly adapted to be accurately centered and fixedly secured axially within a valve guide 30, so that the pilot stem may guide a cutter or surfacing .toolfor accurately. forming or resurfacing a valve seat 28. As the valve seats 28 are surfaces of revolution, it is of the utmost importance that the seats be formed with their axes accurately located in the axis of the valve stem guide, so that the Valves will seat equally at every point upon the seat.

It shouldbe noted that in the present invention the pilot stem 22 is adapted to perform the function of alignment, support and guidance of the cutter 21 upon the tool holder 24, as distinguished from devices in which the pilot'ste'm is merely employed for determining the approximate axial position of the cutter, and it should also be noted that the present method of operation is capable of mathematical accuracy as distinguished from the methods in which a pilot stem is loosely rotated until it assumes the most free posi tion. The latter method merely locates a pilotstem in the approximate axial position, and the accuracy of the latter method depends upon the play between the pilot stem and a'worn valve guide.

Above the cone 32 the pilotstem 22 is pro- 7 videdwith an elongated cylindrical portion 39, which is accurately machined to fit within an elongated and accurately cylindrical bore 40 in the tool holder 24. By means of the complementary elongated cylindrical surfaces 39 and 40, the tool holder 24 is accuratel Y located axially of the valve guide 30 and supported for rotation and reciprocation upon the pilot stem 22-.

At its upper end the pilot stem 22 may be provided with flattened portions 41 for engagement with a wrench in manipulation of the pilot stem, and the bore 40 is of sufficient length so that it is adapted to receive the pilot stem and the head 37 of the camming member in any position to which the tool holder may be fed when used on modern internal combustion engines.

The cutter-21, which has been chosen to illustrate one embodiment of the invention, is of the type employed for cutting a recess inanengineblock for the. insertion of a new Valve seat, and the cutter may comprise a substantially cylindrical metal body 42 made of tempered tool steel and provided with a centrally located frusto-conical aperture 43, which is tapered to form a close frictional fit with the tapered or frusto-conical portion 44 of the tool holder 24.

At'one side, the cutter 21v may be provided with an axially extending slot 45 of substantiallyrectangular cross-section extending inward toward the center of the cutter from its --,outer cylindrical surface. The slot 45 is pref' erably so located that the wall46 of the slot 7 ,H-blade 47 comprises a tempered tool steel memill ber of substantially rectangular cross-section,

which is adapted to fit within the slot 45. At its lower end, the blade 47 is provided with a forward cutting edge 48 on the clockwise side vof the cutter below thewall 46 of slot 45, and "the blade 47 is beveled upward and backward at 49 in counterclockwise direction to permit the cutting edge 48 to come into better cutting relation with the work. In order to definitely locate theblade 47 in its slot 45,"

the cutter may be provided witha backwardly extending heel 50, forming a shoulder 51 which engages the lower flat surface of the cutter body 42.

The cutter body 42 may be provided with i "a second slot 52, comprising a saw cut located substantially parallel to the slot and slightly spaced therefrom. The slot 52is also provided with a bore 53, into which a tapered pin 54 may be driven, spreading the slot 52 and forcing the intermediate 1301431011 55 of the body 42 into engagement with blade to permanently retain the blade in the cutter body. I r

The blade 47 is also provided with a cutting edge at'56 extending axially of the cutter body, and the blade is beveled backward from the cutting edge56 as at 57. The cut ter body 42 is provided with an upper flat surface 58 which is adapted to be engaged by "the lower surface 59 of a bearing member 60 for forcing the cutter into engagement with the work. 7 I I 7 In order to provide means for forcibly feeding a cutter or surfacing tool against the work or valve seat, the complete tool assembly preferably includes a body member 61, which is adapted to be secured to the engine block 26, preferably by means of'the stud .bolts 29, with which the engine block 26 is already provided. The supporting body member 61 is also incidentally adapted to provide auxiliary support for the upper end of the pilot stem 22 and tool holder 24 with- .out, however, changing the alignment of the cutter 21, and withoutpreventing the pilot stem 22 from performing the function of aligning the cutter.

The body member 61 is thus provided with a bearing 23 adapted'to rotatably support the tool holder 24 adjacent its upper end so that the lateral forces which are brought to bear upon the upper end of the tool holder 24 are resisted by th bearing 23 of body member 61.

The body member61 is preferably arcuate in shape, having an elongated'curved body portions 66 and 67. The lower surfaces 68 of the body portion 62 are preferably machined to a substantially plane surface, which is adapted to flatly engage the upper flat surface of the engine block 26.

The. body portion 62 may also be provided with a pair of undercut slots 69 extending along the inner and upper edges of the walls 64 and 65 and adapted to receive the comple mentary dovetail formation upon a washer 71. The body member 61 is widened beyond the end portion 67 to form a bearing portion 7 2, and the walls 64 and 65 may project slightly above the bearing portion 72 so that the bottoms of the undercut slots 69 terminate flush with the upper surface of bearing portion 72.

The washer 71 may thus be removed by sliding itout of undercut slots 69 at the left end of Fig. 2, when the bearing is removed from the body. The washer 71 is thus slidably supported upon the body 61 of the tool,

so that the tool may be located in any of a plurality of positions with a stud bolt passing through slot 63 of the body and bore 7 3 of the washer.

If the stud bolts are longer than the height of the walls 64, 65 a substantially cylindrical spacing member 74 may be placed upon the bolt and the body secured in place by a nut 75., The curved body 61 enables the tool to be secured with ordinary stud bolts in positions where it would otherwise be impos sible. to secure the body on account of the interfere-nee with other stud bolts, and the curvature of the body combined with the plane surfaces 68 at its base gives the tool a greater stability and fixity when secured to the engine block by a single bolt 29.

In order toforcibly cause the cutter 21 to progress into the work, the tool is preferably provided with a feeding member 76 for supporting the bearing 23, and the bearing portion 72 of the body is provided with a vertically extending bore 77 internally threaded to receive the externally threaded portion 78 of the feeding member 76. The feeding member 76 comprises an annular metal memberv having a substantially cylindrical portion 79 provided with relatively fine external threads 78 and having an axially. and centrally located bore 80 of substantially. larger size than the size of the bearing member 60, providing considerable play at 81 between these members. r

At its upper end, the feeding member 76 is substantially increased in diameter, having an enlarged cylindrical surface 82, which is knurled to facilitate a better grip with the 't-heslot 63 and joined at each end by the end member 76 is made .formed in its outer surface and having a cen- 3 5between the inner race 89 and the shoulder hand of the operator or with tools, and form in an engine block.

The enlarged portion 82 of the feeding member '56 is provided with a counter-bore 8%- adapted to receive the outer raceway 85 of a bearing 23, and the upper edge of the feeding relatively thin as at 86, so that the edge 86 may be turned over, as shown in 4, to retain the parts of the bearing 23 in an assembled relation.

The inner bearing member 60 comprises a substantially cylindrical member, substantially smaller than the bore 80 of the feeding member, leaving suficient clearance for a limited universal movement between the feeding member 75., an d the inner bearing member 60 is provided with a reduced cylindrical nor-- tion 87 forming an annular shoulder 88 for definitely limiting the position of the inner race member 89. The inner race member 89 comprises an annular tempered steel member having a pair of circular grooves 90 and 91 trally located bore 92 adapted to receive the reduced portion 87 of the inner bearing member with a forced frictional fit.

A sheet metal washer 98 may beconiined 88 for closing the upper end of the annular space or clearance 81. The ball bearngs 94- are assembled n the grooves 90 and 91, and supported in staggered relation to each other ..by a ball ring .95, and the outer race 85 is provided with a single concave groove 96 of circular cross-section, which is adapted permit a universal movement between the outer race 85 and the inner race 89, the ball bearings 94 moving with the inner race 89. The. groove 96 has a substantially spherical surface formed at a radius equal to the distance from the center of the bearing to the surface of groove 96.

The counter-bore 84 maybe provided *ith a' flexible fabric washer 97, after which the inner bearing member 60, inner race 89, balls 7 94 and outer race 85 may be placed in counterbore 84. Asecond flexible fabric washer 98 .may be placed above the bearing, after which a plurality of spring washers 99 maybe placer. about the reduced portion 87. A sheet metal washer 100 may then be placed above the spring washers 99 and secured in place by riveting over the upper end 101 of the reduced portion 8?. The bearing assembly may be retained within the feed member 76 by a dished sheet metal member 102, having an enlarged bore 103, and having its outer edge 104 secured between the race 85 and the tur ed over dge 86 of the feed member 76. The dished portion of the dished member 102 is adapted to provide space for the spring washers 99, an it should also be noted that 'the metal Washer 100 is of smaller size than.

er era the dished portion of the member 102, so as to permit the washer 100 to slide aboutin the dished member 102 when pivotaloruniversal movementftakes place between the feeding member 7 6 and the inner bearing member 60.

The spring washers 99 are illustrated in detail in Figs. 6 and 7, and they may comprise tempered sheet metal members of annular shape which are provided with the diametrically opposite flat portions 105 bent up out of the plane of the flat portions 106 of the spring Washer 102.

The inner bearing member 60 is provided with an accurately machined, centrally and axially located bore 107, adapted to slidably and rotatablyreceive the cylindrical outer surface 108 of the tool holder 24. The upper end of the tool holder 2% may be provided with atransverse bore109 for receiving hand levers or rods used in oscillating the tool holder 24 and with a non-circular end or head 110 adapted to receive the ratchet lever 25.

It will=thus be observed that the bearing member 23 is adapted to rotatably support the tool holder 24land cutter 21 upon an axis which is determined by the position of the pilot stem 22, and the inner bearing member 60 is adapted to pivot universallyrto permit the tool holoer 24 to assume the position determinedby the pilot stem. The universal on the upper surface .58 of the cutter body 42t force the cutter into engagement with the work. 7 r

The bearing 23 constitutes ananti-friction thrust bearing which is adapted to permit limiteduniversal movement, so that the feeding member 76 will; provide a substantially axial feeding force upon the cutter 21 at all times. The cutter may be fed into the valve seatby rotating the feeding member in a clockwise directionin .Fig. 1, causing the inner bearing member 60 to progress axially of the pilot stem 22.v WVhen the feeding member 7 6 is thus actuatech and the cutter 21 is employed for resurfacing or cutting a recess, the forcewhich is brought to bear upon the cutter 2lmay be increased as desired although the amount of friction which would be present in an ordinary bearing would be such as to require a large proportion of the effort for merely overcoming the friction of the hearing as distinguished from a cutting operation. With the present construction, however, the cutter 21 may be fed quite rapidly into the engine block and the cut accomplished with ease; thereby,

greatlydecreasing the amount of time and to the position of the valve guide, and incidentally the bearing 23 is adapted to resist lateral forces applied to the head 110 of tool holder 24 by ratchet lever 25, which forces might otherwise tend to bend a relatively slender pilot stem. c o

The bearing portion 72 of the body mem ber 61 is preferably provided with a bore 111 extending substantially parallel to the bore 77 and adapted to slidably receive a pin 112 having a head 113. The bearing portion 72 is also providedwith a threaded bore 114 extending transversely to the bore 111 and communicating therewith, and the bore 114 is adapted to slidably receive the cylindrical end 115 of the threaded bolt 116. The bolt 116 is provided with a transverse bore 117 adapted to register with the bore'111 and adapted to receive pm 112, and a spring washer 118 and a wing nut 119 are provided, securing the bolt 116.'

hen the parts arein the position of Fig. 4, and the wing nut 119 is threaded in a clockwise direction on bolt 116, the bolt 116 is drawn out of its bore 114, clamping against the pin 112, and securing the pin 112 in any adjusted position. The pin 112 with its securing means comprises an adjustable gauge I for determining the amount of feed required to make a predetermined depth of cut.

The pilot stem 22 is also adapted to be used with the assembly of parts shown in Fig. 10 for inserting a new valve seat ring 120 in the recess 121 formed by the cutting tool 21. The ring 120 comprises an annular metal member which maybe constructed of tempered steel or any other material desirable for a valve seat. The body of the ring 120 is preferably of substantially rectangular cross-section and adapted to be secured bv close frictional fit within the complementary annular recess 121', made by cutting tool 21. 7

The ring 120 is preferablyinstalled by using a driving tool 122 and comprising a substantially cylidrical metal member having an accurately machined, axially extending and centrally located borec123,'adapted to slidably rcceivethe cylindrical portion 108 of the tool holder 24. V

The body of the driving member 122 forms a handle which may beknurled as at 124 for convenient manipulation, and the upper end of the driving tool forms an impact surface 125 to be engaged by a hammer or other driving tool. 126 of the driving tool is substantially fiat and may be enlarged, if necessary, to correspond to the diameter of the ring 120, forming an annular flange 127, adapted to extend over and'to engage above the top of the ring 120.

The method of use of the driving tool 122 will be explained in detail hereinafter, but

' itshould be noted that the pilotstem '22 is The lower surface highly advantageous for guiding the driving member 122 in driving a ring 120 into a close frictional fit in the recess 121. The pilot stem is adapted to support the driving tool axially of therecess 121, so that the ring is forced in at all sides of the recess simultaneously, without trouble or without damaging the ring, an operation which'is rendered much more difficult without the use of the pilot stem. hen an effort is made to insert a ring without theuseof'the pilot stem, the tendency is to drive the ring in at. an angle so that the walls of therecess may be damaged, or the ring seated at a tilt, or the ring may be so damaged that it will not properly seat in the recess thereafter.

The present valve seat tool may be employed with roughing reamers or other surfacing tools for accurately resurfacing valve seats and the operation of resurfacing a valve seat is greatly simplified and the labor lessened by the use of the present tool. The feeding device is adapted to permit a heavy force to be brought to bear upon the roughing reamer, so that the operation may be done in a small portion of the time otherwise necessary, and the universal bearing provided is adapted to permit the feeding operation without disturbing the alignment determined by the pilot stem fixed in the valve guide. v 9

It will thus be observed that the present device is adapted to effect a rapid and accurate resurfacing of valves with a minimum of eflort.

The device may also be employed for entirely removing the metal surface of an old valve seat, forming a recess adapted to receivea new metal ring for forming a new valve seat.

The mode of operation of the valve seat=1 tool is as follows: The pilot stem 22 may be inserted in the valve guide30 and given a slight tap with a hammer to seat the cone 32 in the guide 30 and center the pilot stem at cone 32. A wrench or other tool may then be applied to the head 37 of the camming mem her and by turning in a clockwise direction, the camming member will force the tripartite end 31 apart, engaging the valve guide 30 and accurately centering the lower end of 1 the pilot stem. The pilot stem 22 is then located axially and centrally of the valve guide 30, as distinguished from devices in which the pilot stem is loosely received in the valve guide. 0 The camming member 34 may be threaded into the pilot stem 22 beyond the point neces- V sary to cause the lower end of the pilot stem to engage, thereafter placing compression :upon the camming member 34 and placing the pilot stem 22 in tension, and greatly stiffening these members. 1

The tool holder 24 and cutter 21' may then be placed upon the pilot stem 22, the tool holder being slidably and rotatably received 130 member-6O and body member 61.

cutter 21' will have its axis accurately locatedin the axis of the valve guide 30, and the valve ean be seated upon such a surface with equal sealing effect at all polnts.

} overan adjacent stud bolt 29 with'the tool hol'derf 2-1- in tlie'inner bearing member 60, and the position of the body 61 on the engine bleak will-be determined by the position of the pilot stem 22. The body 61 is then secured to the engine block 26 by the nut 75, with or without a spacing member 7%, as required by the particular length of-stud bolt, and the bearin -23 will ad iust itself axiall of the I b e d n a n I pIlotstem'22-,'smce a limited unlversal movement lspermltted between the inner bearlng Thecutter' 21 -may now be fed downward "-b rotatin the feedin member 6 in a clock- '-wise"direction;- sothat the feeding member progressesdownward in the'bore 77, carry- "25 ing with it the bearing 23, including the inner bearing-member 60. The inner bearing member 60 is broughtinto engagement w1th the 'top of the' c'utter body 42, after which the" inner bear-ing member GO-reacts against the ball bearings 9 1 by means of grooves 90 and 91 ,'-a-nd= the ball bearings react against groove 96 "whichnermits the inner-bearin member to" adjust itself-universally, but which is adapted to resist axial thrust.

"" Any desired pressure may be brought to 'bear upon the cutter 21 "by means of the universal ball -bearing: 23 without causing the hea-ring to loindyandthe cutter may be'rotated' with ease byapplying the ratchet lever 25 or m -other tool'to'the non-circular head 110.

Itishould also-benoted that the universal bearing-23 ispeculiarly adapted to permit I 'thecutter 21 to be constantly maintained .iali'gned in axial position with valve guide 30 =by-pilotistem 22,'and this constant alignment fcould notlbe accomplished by an ordinary 'bearing. iItis practically impossible to cuta feedingzmember' 76 with threads '78 which iarelocatedaccuratelyrelative to the axis of l the feeding member, because the threads are ::commonly outwith a cutter which feeds and r'gu-i'des itself, and'if the metal is softer on one -rside, :the threads will-be cut deeper, and where :theametal v-isi harder, the threads' will -60-ofthe universal bearing used at the upper end of the tool 'holder.

If the operation to be performed is merely wa resur-faeing "operation, it isunnecessary to L --use any gauge;andthe resurfacing tool is zt5a=merely actuated by the ratchet lever 25 until guide 30, since thealignment of the present is proposed toinsert is held with its upper ithe outs'id e diameter tool with tool holder Zlandicutter 21' every partlof the surface has been refinished.

It ShOdlClgbQ, noted that the new surface cut accurately located in the axis of the valve device does not depend on the use of a loose pilot'supported in a position in which it ro- The supporting body 61 may then be placed tates. most freely, -but the alignmentis accomplished by a self-centering pilot permanently fixed with its axis in the axis of the is'first setup asrshownin Fig. l, with the cutter blade. 47 resting upon the upper edge of the engine block 26, the ring which it surface against the shoulder-83, and the head 113 of'the pin 112 is moved up until it engages thelbottom of the ring 120, the pin being secured by turning wing nut 119 clockwise. 790

-After this', the icutt er maybe rotated by :means of the ratchet lever 25 while the feedingsmember 76- is also constantly fed downward by rotating-said feeding member clockwisefand the cutting'operation proceeds quickly until an" ann ulargroove -121 of a *shape complementary to the ring 120 is 'formed'in the engine block 26. The feeding :movementmay progress until shoulder 83 'en'gages-head 1130f the gauge member 112, when the depth of groove121 will correspond cuter 21 to" the thickness of ring' 120. The

has of eourseybeen constructed with its outer *cutt1ngedge 56 so located relative to the axis of c utter 21 that the diameter of the recessed portion of the valve seat is slightly less than of thering 120, so that the ring 120 may be driven into a close'fric- F The 'entire"body 61 of the reconstruction 110 may be removed by loosening the n'ut75, leaving the pilot? stem '22 in accurately aligned position invalVegu'ide'ZEO. Aring then be placed over the pilot stem22 above the inner groove 121, but a s the ring is larger than the diameter of the recessed" portion of the-block, the ring will 'remainabo'vethe face of the'engine block. -The cutter 21 maybe removed from tool #55 be more shallow. Consequentlyyit will be holder"24-and t0ol holder 24 replaced upon' pilot stem -22,

1Thetdriving'tool122 may then he placed with fits bore 1123 about the cylindrical por- :tion 108 of tool holder 24;, and tl1e ring12O maybe .loca-ted with the fingers, directly above the annular" groove 121 and held flatly against the bore surface 126 of driving tool 122. The ring may'then be quickly: driven "llltOithGfl'ECGSS 121 by a few blows of a hammer ,upon trmpactisurface' 125 of: driving tool 39 122, during which time the pilot stem 22 will hold the driving tool 122 axially of the annugroove 121, so that the ring may be driven in axially with a few blows until it seats itself against the bottom of the groove 121.

It should be noted that since the valve seat ring 120 is constructed of relativelyhard resilient metal, such as tool steel or an iron alloy having the qualities of heat resistance and uniform hardness, the ring ordinarily tends to spring back out of the annular groove 121 until it has been well started and the operation of driving the" ring without the driving tool 122 or pilot stem 22 is a very difficult matter, consuming more time and tending to damage the ring.

If the ring is of greater diameter than the standard driver, an extension driver or adapter, comprising an annular spacing i ember of greater diameter than the annular portion 127 of the driving tool, may be used. The adapter or extension driver is placed over the pilot stem 22, above the ring and below the driving tool 122. I

If the combustion chambers are counterbored, a cutter spacer may be inserted between the upper surface of the cutter and the lower surface of the inner bearing member 60. The spacer 74 is exemplary of each of the spacers herein described, except that the size of the spacer may be varied to lit the parts with which it is to be used.

If the valve seat ring protrudes above the surface of the block the ring may be faced off flush with the block by using the cutter 21, after which the valve seat may be cut in the usual manner with a reamer or surfacing tool.

The driving tool 122 is also adapted to be used to remove the cutters from the tapered portion 44: of tool holder 24 by simply placing the driving tool above the cutter on the tool holder, resting the end of the pilot stem on a block and tapping the cutter free.

It will thus be observed that the valve seat tools of the present invention are peculiarly adapted to be aligned with mathematical accuracy with the cutter axis coinciding with the axis of a valve guide, and the accurate alignment of the tool is accomplished by means of a pilot stem fixedly secured in the valve guide. The separate parts of the machine are, of course, of general application and may be used with any pilot stem, but the most accurate results can only be obtained when the pilot stem actually fits valve guide 30, or when a pilot stem of the type described,

capable of accurate, axial centering,is used.

The present method of reconstructing valve seats comprises the following steps when the entire method is employed, although various subcombinations of the steps may also be used with advantageous results: A pilot member is first placed in a valve guide and located axially of the valve guide at one point of the length of the pilot member, after der the state of tension to stifien the same and fixedly secure it within the valve guide, after which the cutter with its tool holder may be placed upon the pilot stem, the complementary surfaces of these parts accurately aligning the cutter with its axis in the axis of the valve guide. The cutter is now guided by the pilot stem to perform a cutting operation, which will either cut a recess for a new valve seat ring or resurface a valve seat, and in either case, the surface formed will be a surface of revolution having its axis at the center of the valve guide.

The cutter may also be guided by the auxiliary support providedby bearing 28. Since the bearing 23 is a universal hearing it can only provide an auxiliary support against lateralrmovement of, the tool holder or pilot and a thrust bearing against which the feeding member may react, so that the bearing 23 only assumes a position w iich is determined and maintained by the pilot member. The cutter may then be fed axially of the pilot: stem by means of the supporting body with its feeding member and rotated about the axis of the pilot stem by any convenient source of power to cut a groove or resurface a valve'seat.

If a groove has been cut, the next steps in the reconstruction of a valve seat are the placing a ring above the recess, guiding a driving tool by means of a pilot member, and driving the ring into frictional engagement with the walls of said recess to seat the ring in the re cess. I v I The ring may then be cut off flush with the surface of the block, using the same method previously described and the valve Seat may be formed by using a cu ter of appropriate shape according to the same method.

While I have illustrated a preferred embodiment of my invention, many modifications may be'made without departing from the spirit of the invention, and l do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, what I claim is new and desire to secure by Letters Patent of the United States, is

1. In a valve construct-on tool, the combination'of a pilot member adapted to he fixedly secured in a valve stem guide incenteredposition, with a tool holder rotatably and slid ably mounted on the upper end of said pilot, a

valve seat'tool carried by said holder and having a cutting edge for engagement with 'spect to the a valve seat, a reinforcing fixturehavinga body adapted to be fixedly secured to theengine blOCk,StIiCl fixture being formed with a threaded bore adapted to be brought into substantial alignment with the axis ofsaid pilot, a feeding sleeve having an external threaded arface adapted to be received in said bore, a guide sleeve having-a cylindrical bore adapted to rotatablyand slidably receive the upper end of the tool holder said 'guide sleeve having its lower end in engagement'with the upper surface of said tool and a universal bearing interposed between said feed sleeve and said guidesleeve whereby said tool holder and cutter may rotate freelywith respect to said feed sleeveand said tool holder and cutter are free to align themselves with-repilot during the rotation of the cutter.

2. In a valve construction tool, the combination of a pilot member adapted to be fixedly secured in'a valve stem guide in centered position, with a tool holder rotatably' and slidably mounted on the upper end ofsaid pilot, a valve seat tool carried by said holder and having a cutting edge for engagement witha valve seat, a reinforcing fixture having a body adapted to be fixedly secured to the engine block, said fixture being formed with a threaded bore adapted to be brought into substantial alignment with theaxis of'said pilot. a feeding sleeve havingan externalthreaded surface adapted to be received in said bore, a guide sleeve having a cylindrical bore adapted to rotatably and slidably receive the upper end of the tool holder saidguide sleeve having its lower end in engagement with the upper surface of said tool, a universal bearing interposed between said feed sleeve'and said guide sleeve whereby said tool holderand cutter may rotate freely with respect to said feed sleeve and said tool holder and cutter are free to align themselves with respect to the pilot during the rotation of the cutter, said universal bearing comprising an outer race carried by said feed sleeve and formed with a curved annular groove havingits center ofcurvature substantially in the axis of the tool holder, a plurality of anti-friction balls in' said race and freely movable transversely with respect to said race on said center of curvature, and a second race carriedby said guide sleeveand adapted to engage said balls to retain them in said races.

3. In a valve construction tool, the com bination of a pilot member adapted to be fixedly secured in a valve stem guide in centered position, with a tool holder rotatably and slidably mounted on the upper end of said pilot, a valve seat tool carried by said holder and having a cutting edge for engageeassess into substantial"alignment with the axis of said pilot, a feeding sleeve an'external threaded surface adapted to be received in said bore, a guide sleeve having a cylindrical body adapted to rotatably-and slidably receive the upper end of the tool holder said guide sleeve having its lower end in engagement'with the upper surface of said tool,a universal hearing interposed 'betweensaid feed sleeve and said guide sleeve whereby said tool holder nular shoulder carried bysaid feed sleeve" and'adapted to engage said stop pin to limit the feeding movement of said feed sleeve and determine the depth of cut.

In witness whereof I hereunto subscribe my name this 12th day of February, 1929.

FRANS' O. ALBERTSON.

ment with a valve seat, a reinforcing fixture r having a body adapted to be fixedly secured to the engine block, said fixture being formed with a threaded bore adapted to be brought 

